Chemistry

The half-life of oxygen -15 is 124 seconds. If a sample of oxygen -15 has an activity of 4000 becquerels, how many minutes will elapse before it reaches an acivity of 500 becquerels

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asked by Elisabeth
  1. Calculate k from k = 0.693/t1/2 and substitute into the following:
    ln(No/N) = kt
    No = 4000
    N = 500
    solve for t, which will be in seconds, and convert to minutes.

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    posted by DrBob222

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